The present invention relates generally to mass transit fare collection systems and, more specifically, to communication between a vehicle and a station terminal.
Many mass transit systems may have sophisticated data collection and analysis capability. Data in the form of fares collected, the destinations and times of use by patrons, and other information are collected from the transit vehicles and stations and analyzed at a central facility. The results are used to develop more responsive scheduling and allocation of equipment, detect and prevent revenue losses, plan maintenance and improvements, integrate with other transportation systems, and generally assist in the overall management of the transit system. Data is commonly also provided by the central facility to the transit vehicles and stations in the form of scheduling information, fare tables, blacklisted fare cards, and the like.
Data communication between a central facility having data analysis capability and stationary parts of the transit system, such as fare collecting turnstile systems, is commonly via permanent hard-wired lines connecting the station to a central computer system. Data communication between the central facility and mobile parts of the transit system, such as trolleys and buses, is more difficult if patrons do not pass through a stationary turnstile connected to the central facility. Typically, the fareboxes of such vehicles include electronic memories for storing data in addition to an electromechanical coin collection system. Periodically, it is necessary to transfer some of the data in the farebox memory, such as data concerning fares collected, to the central facility. It may also be necessary to update data in the farebox memory, such as data concerning scheduling and fare tables. Such data transfers may be performed daily.
When the transit vehicle returns to a central facility, the accumulated coins or tokens are removed from the farebox by a suction hose. At the same time, information may be transferred between the farebox and a computer at the facility. To establish the data link, a technician commonly maneuvers a cable into the vehicle and inserts the connector on the end of the cable into a mating connector on the farebox. Practitioners in the art have recognized that forming a good electrical connection is a problem because the facility is likely to be inhospitable to delicate electrical connectors. Grease and grime, soot from diesel engine exhaust, and even oils from the technician's perspiration may foul electrical contacts, resulting in unreliable data communication. Practitioners have reduced the effects of the harsh transit environment by using optical connectors. A transparent window at the end of each connector permits light from an infrared transmitter in one connector to be transmitted to an infrared receiver in the other connector. However, the two connectors must be carefully aligned to allow enough light transmission for reliable operation. In addition, the optical windows must be kept clean. Furthermore, the optical connectors are relatively fragile and must be handled carefully to avoid damage.
Since data communication is an increasingly important function in a transit system, there is a need for an improved data communication system and link from a transit vehicle to a central station. Such a system must be tolerant of misalignment of the connectors, must permit high data communication rates, and must be rugged and resistant to the harsh environment of a transit system. These problems and deficiencies are clearly felt in the art and are solved by the present invention in the manner described below.